Apparatus for testing and adjusting carburetors



H. D. GREEN July 21, 1936.

File'd Dec. 24, 1954 W 4 T u n MPH I 1 w m a .fi

ATTOR NE Y Patented July 21, 1936 UNITED STATES PATENT OFFICE APPARATUS FOR TESTING AND ADJUSTING CARBURETOBS 11m 1). Green, Atlantic, Mass.

Application December 24, 1934, Serial No. 758,894 7 Claims. (Cl. 73-51) This invention relates to a device for testing and adjusting carburetors for internal combustion engines, and for visually indicating the rate of fuel consumption by an internal combustion engine.

Carburetors as commonly constructed utilize the suction action of the engine to draw air past.

the fuel inlet nozzle so as to form an explosive mixture that is drawn into the cylinders. The

efficiency with which an engine operates and the amount of fuel it consumes therefore depends to a. considerable degree upon the strength of the suction produced in the manifold of the engine.

Therefore in tuning up an engine andadjusting the carburetor it is important to determine whether or not the suction produced by the en-' gine is proper, and if the suction is defective it should be corrected before attempting to secure the final adjustment of the carburetor.

Heretofore in many cases the adjustment of carburetors has beenlargely a matter of guess work without accurate knowledge being had as to the degree of vacuum produced in the engine manifold or the rate of fuel consumption by the carburetor for different engine speeds.

The present invention therefore contemplatesa device for use in securing the proper adjustment of an engine carburetor to obtain maximum power and minimum fuel consumption, and its use consists in first determining by vacuum readings the suction action produced in the engine intake manifold, correcting as far as feasible any defects in the engine operation indicated by the vacuum readings, then visually determining the rate of flow of fuel to the carburetor and adjusting the carburetor to secure the lowest fuel consumption obtainable at one or more speeds for theparticular suction action of this engine.

- One importantfeature of the present invention I being graduated for use in testing thecarburetors of engines in small or average size automobiles and the other for testing the carburetors of larger engines such as used in trucks and busses, and provided with a constant level chamber for supplying fuel to these tubes through calibrated oriflees so that the rate at which fuel enters these tubes will vary with the head pressure or the level of the fuel in a tube below that of the fuel in the constant level chamber. Y

A further feature resides in the valve arrange- 'ment for placing one or the other of these tubes 5 in operation to supply an indicated flow of fuel to the carburetor being tested, and in the construction and arrangement whereby the carburetor may be tested without resorting to a road test.

Still a further feature resides in the construction and arrangement whereby the adjustment of the control valve to a position to take a reading from either one of the tubes causes the other tube to fill rapidly in readiness for the" taking of a reading therefrom. In this manner an intimate cooperation between the control valve and the two sight tubes is obtained whereby the filling of one is secured while the other is being emptied.

Other features of the invention and novel combination of parts in addition to the above will be hereinafter described in connection with the accompanying drawing which illustrates one good,

. practical form thereof.

In the drawing:

Fig. 1 is a. front elevation of a box or casing provided with the indicating mechanism of the present invention.

Fig. 2 is an elevation of the rear face of the door of the box of Fig. 1 showing the mechanism mounted thereupon.

Fig. 3 is a sectional view taken on the line 3-3 ofFig.1.' w 5 Fig. 4 is a diagrammatic view of a valve and calibrated apertured connections to be described; and

Fig. 5 is a diagrammatic view showing the present testing device in use.

The testing device of the present invention is designed for use primarily by automobile repair 40 men and is therefore shown as mounted in a portable box or casing conveniently formed of wood, and having a door or front wall Ill-which is secured by hinges I l to a side wall I2 of the box having the rear wall l3, and a fastener it serves to hold the door closed.

The door I0 is shown as having a hole formed therein of a size to snugly receive a vacuum gage l5 for testing the engine. This gage may be of well known construction and adapted to .give vacuum readings from say 1 to 30inches of merc'ury. The face of. the gage dial, however, is es pecially marked,-as will behereinafter described. to facilitate testing and adjusting the engine. The gage l5 has a needle [6 that travels over the 55 face'of the dial and the gage casing may have the usual threaded nipple I! that is shown as secured to a bracket It. This bracket is secured by screws to the rear face of the door It, and a tube It pro-' 'iecting from the bracket leads to the interior of the gage. In the embodiment of'the invention shown the carburetor testing device is provided with two sight tubes for use in indicating the rate of fuel consumption. One tube is designed for use in testingfcarburetors for-the smaller and ayera'ge size automobiles and the other tube 2| is designed vided with a scale 23 which is provided to indicate a gasoline consumption from 0 to 2.7" gallons per hour. The tubes 20 and 2| are preferably mounted in grooves formed in the face of the door It as will be apparent from Fig. 3. Upon the inner face of the door I, in the construction shown, is mounted a constant level supply casing 24, which may be of well known construction, and has a valve stem 25. secured to-a float valve lever 26 pivoted at 21 and provided with the float 28. The arrangement is such that the gasoline or other fuel will remain at a constant level in the casing 24 which may have the cover 29.

Provision is made for supplying the fuel from the casing 24 to the glass tubes 20 and 2| so that it may rise in these tubes to the level of the fuel in the casing 24, and to this end, in the construction shown, a pipe 30 is provided at the rear of the door l0 and extends downwardly from the casing 24 to near the" lower end of the tubes 20 and 2|. The pipe 30 preferably has. an'air vent tube 3| extending upwardly above the level of the fuel in the casing 24, and the upper ends of the tubes 20 and 2| are vented.

In the construction shown the lower end portion of the tube 20 is connected with the pipe 30 by the laterally. extending pipe 32 and by a by- Pa pipe 33, and the tube 2| is similarly con nected with the pipe 30 by the laterally extending pipe 34 and by-pass pipe 25, so that each tube 20 and 2| has two lateral connections with the fuel supply pipe 30. The coupling 36 for the pipe- 33 is preferably providedwith a small calibrated orifice adapted to retard the flow of fuel" from the pipe 30 to the tube 20 through the bypass pipe 23, and the coupling 31 has a larger calibrated orifice that serves to retard the flow of fuel from the pipe 30 to the tube 2| through the by-pass pipe 35'.

A valve casing 38 serves to connect the lower end of the pipe 30 to the laterally extending pipes 2 2 and 34 and the flow of fuel from the 'pipe 20 to the pipe 22 01*34 is controlled by the rotating valve 29 as will be appa ent from Fig. 4. When the valve 39 which has a pointer 40 is turned to the position marked Small motors". (see Fig. 1) the pipe 24 leading to the tube 2| will be connected with the suply pipe 20, and the pipe 32 leading from the tube 2| will be connected with the discharge pipe 4| extending downwardly from the valve casing 32. If the. valve 29 is turned to the position marked Large motors" fuel will be supplied to the tube 20 from the pipe 20 through the pipe 22 and will be permitted to flow from the tube 2| through the pipe 24- to the discharge pipe 4| as will be apparent from Fig. 4 in which 8 indicates the small motors" position and}! the y-lpipes 32 and 24, as will be apparent from Fig. 4. 5

When it is desired to employ the testing device" of the present invention to test and adjust the carburetor of an engine such, for example, as an automobile engine, the wood box or casing l0, l2, I! may be supported from a post or otherwise near the automobile engine, and the vacuum ga e It may then be connected with the intake manifold 42 of an internal combustion engine 43 by a rubber tube or the like 44 leading from the manifold to the tube ll.

The usual pipe connection 45 leading from the automobile fuel supply tank 46 to the engine carburetor 41 may be disconnected and the tank 46 is connected with the constant level casing 24 of the, present device by a flexible pipe 48, sothat 2 the usual fuel pumping means (not shown) will feed the fuel from the tank 46 .to the casing 24. This casing should be supported at a sufficient height above the level of the carburetor 4'! to secure a gravity feed through the pipe 49 from 25 the-valve casing 2! to the carburetor 4I.

The testing device-of the present invention is now ready for taking readings and one or both rear wheels of the automobile may be jacked up fective in this respect the necessary corrections should be made, for example, by correcting the action of the engine valves, piston rings, spark gaps or timing mechanism.

After these corrections have been made as com- 40 pletely as the general condition of the automobile or other controlling condition may warrant, then I the carburetor should be tested and adjusted to secure the lowest fuel consumption, as indicated in the sight tube 20 or 2|, that can be obtained for the suction action of this particular engine at different speeds. When the float casing 24 of the present device is supplied with fuelland the valve 2! is turned to the closed position fuel will flow through the 50 pipe 20 and by-pass pipes 32 and 35 into the tubes 20 and2| to'rise slowly therein to the level of the fuel in the casing 24. Now if thevalve 39 is turned to the small motors" position, and the motor is started, the fuel will remain at the-zero point near the top of the tube 2|,-but .will fall in the tube 20 as the fuel feeds from this tube to the carburetor, until it comes to rest at the grad,

uation say 1.05" which will indicate the rate at A which the fuel is being consumed by the carburetor at a particular speed. If the carburetor is then adjusted to require less fuel this will be' promptly shown by the rising of the fuel in the tube 2| to a position say which shows the fuel saved by the better carburetor adjustment. 65 2 If the tube 20 will not supply the fuel to the carburetor fast enough, then the valve 29 is turned pressure, and when the fuel level falls in one of these tubes the rate at which the fuel passes" through the calibrated orifice increases, substantially in proportion to the square root of the head pressure until it equals the carburetor consumption at that time, which is shown by the height of the fuel in this tube. I

It will therefore be seen that by employing the carburetor testing device of the present invention the amount of gasoline being consumed by the engine at different speeds and for different carburetor adjustments is readily determined .by noting the height of the gasoline in the tube 20 or 2! being used and the reading of the scale at this height.

, Since the by-pass pipes 33 and 35 are provided with the small calibrated orifices 36 and 31 respectively, the tubes 20 and 2| will fill slowly through these by-passes. It is, therefore, desirable to provide means whereby either tube may be filled quickly ready for a reading and also whereby one tube may be quickly filled while the other tube is being used in testing the engine. This is accomplished by employing the valve construction shown which operates to establish a connection between the tube 30 and one pipe 32 or 34 when the other pipe is connected with the discharge pipe 4|.-

' lies in the black section indicated by d proper or normal motor conditions are shown.

I claim:--

1. A device for determining the rate at which fuel is consumed by an internal combustion engine, comprising in combination a pair of sight tubes, a constant level supply chamber connected to the sight tubes, a discharge conduit connected with said tubes to discharge the fuel from either tube at a common point, a by-pass connection provided between said supply chamber and each tube, a calibrated orifice .in one by-pass and a larger calibrated orifice in the other by-pass, and

means associated with said connecting discharge -conduit for placing one tube or the other in operation to determine the rate of fuel consumption and also operable to fill the other tube from said supply chamber.

2. A device for determining the rate at which fuel is consumed by an internal combustion engine, comprising in combination a pair of sight tubes, a constant level supply chamber, a discharge conduit connected with said tubes to discharge the fuel from either tube at a common point, a by-pass connection provided between said supply chamber and each tube, a calibrated orifice in one by-pass and a larger calibrated orifice in the other by-pass, means'for connecting the supply chamber to the sight tubes through said conduit, and valve means associated with said discharge conduit and adjustable to one position to effect a fiow of fuel through one by-pass into its tube and from that tube through said conduit and adjustable to another position to effect a fiow of fuel through the other by-pass into its tube and from this second tube through said conduit, whereby fuel is admitted to one tube through said conduit while it is being discharged from the other tube.

3. A device for testing carburetors, comprising in combination, a pair of sight tubes each provided with graduations for indicating the rate of fuel consumption, a constant level supply chamber having a pipe leading to the lower portion of each tube, a second connection including a calibrated orifice between said pipe and each 'tube, whereby two means are provided for filling each tube one through said orifice and the other more rapidly, a conduit for delivering the fuel from the sight tubes to the carburetor, and valve means for placing either tube in operation to test the car'- buretor .and operable also to control the means for rapidly filling the tube.

4. A device for testing carburetors, comprising in combination, a casing having a front wall, a

pair of sight tubes mounted upon said wall and provided with graduations for indicating the rate of fuel consumption, a constant level supplychamber mounted within the casing, a discharge conduit connected to the two tubes, means forconnecting said discharge conduit to a carburetor, means for connecting said chamber to each tube through said conduit, a by-pass provided with a calibrated aperture for supplying fuel from said chamber to one tube and a by-pass provided with a larger calibrated aperture for supplying fuel from said chamber to the other tube, and a valve associated with said conduit and operable to place .one tube or the other in operation to determine the rate of fuel consumption and. operable also to rapidly fill the other tube through said conduit.

5. A device for testing carburetors, comprising in combination, a pair of sight tubes each provided with graduations for indicating the rate of fuel consumption, a constant level supply chamber, means for connecting said chamber to the two tubes, calibrated orifices provided in the connections leading from the supply chamber to each tube, a common discharge pipe for the two tubes,

means for connecting said discharge pipe to a carburetor, conduits connected to said supply- 6. A device for determining the rateat which fuel is consumed by an internal combustion engine, comprising in combination. a pair of sight,

tubes, a constant level supply chamber, means for connecting said chamber to the two tubes, a calibrated orifice provided-in said connection between the supply chamber and one tube and a larger calibrated orifice provided in the connection between the supply chamber and the other tube, acommon discharge pipe for the two tubes, means for connecting said discharge pipe to the engine to be tested, conduits connected to said supply chamber 'and leading from each sight tube to said discharge pipe, and a control valve associated with said conduits and constructed and arranged to control the flow therethrough into each tube and discharge therefrom, to thereby selectively place either one of the.tubes in operation to test the engine while the other tube is supplied with fuel from the suptubes, a constant level supply chamber, a conduit connected to said chamber and to the lower portion of said tubes and having a discharge pipe through which either tube may discharge, means for connecting said discharge pipe to the engine to be tested, a control valve associated with said 3 conduit and discharge pipe and constructedand arranged to control the flow therethrough to each each by-pass.

tube and the discharge from each tube through said pipe, to thereby selectively place either tube in operation to test the engine while the other tube is supplied with fuel from the chamber through said conduit, aby-pass between each tube and said conduit, and a calibrated orifice in n'owann n. GREEN, 

